top of page

How to Grow Watermelons

Updated: Feb 14, 2022

North Texas is a great place to grow watermelon plants. They absolutely love our hot, sunny environment, which is why Texas is one of the highest producing states for watermelons.

Native to Africa, watermelons have been cultivated for at least 5,000 years. We know the ancient Egyptians loved watermelons because they depicted the fruit in drawings on the walls of tombs and even left watermelons with their dead to nourish them as they journeyed through the underworld.

Man holding watermelon plant in front of his face.
Watermelons are native to Africa

Did we say watermelon is a fruit? We meant to say it’s a vegetable. The watermelon actually belongs to the cucurbit family, and is related to pumpkins, cucumbers and squash. It’s also 92% water. In fact, early explorers often used watermelons as canteens to carry extra water.

Forget the myth that watermelon seeds will grow in your tummy. They don’t. But the seeds are highly nutritious with high levels of magnesium, zinc and protein. Just be sure to chew them up before swallowing for optimum nutrition. Watermelon is also low in calories — only 40 calories per cup, yet it has more lycopene — a powerful antioxidant ­— than any other fruit or vegetable. Watermelon is also high in vitamin C and a good source of fiber.

Best Watermelon Varieties For North Texas

Watermelons are big! Small varieties can weigh 10 lbs, while larger types can tip the scale at 200 lbs! In general, the bigger the watermelon variety, the longer it will take to reach maturity. Most watermelons mature in 85 to 100 days, while some need up to 130 warm days to ripen. (Days to maturity measures the average number of days from seed germination until harvest.)

Popular varieties sold at Marshall Grain are:

  • ‘Sugar Baby’: 80 days. Produces 10 lb melons with bright red flesh. This smaller variety can be planted just 4 feet apart.

  • ‘Charleston Gray’: 87 days. Produces long gray-green skin and red flesh. Fruits can grow to be 20 - 40 lbs.

  • ‘Crimson Sweet’: 80 days. Large, round melons averaging 25 lb. are light green with dark green stripes. Flesh is dark red, firm and fine-textured. Resistant to Fusarium Wilt and Anthracnose.

  • ‘Jubilee’: 90 days. Long, oval-shaped fruit with red flesh.

  • ‘Black Diamond’: 90 days. The ‘Black Diamond’ is the quintessential watermelon. Also called the “king” of watermelons, it can weigh as much as 50 lbs. Its sweet, juicy flesh is bright red and tender.

watermelon planting tips

When to Plant Watermelon Plant

Watermelons are easy to start from seed. We recommend that you sow them directly into the soil outdoors, rather than going through the process of hardening them off and then transplanting.

As much as they love the heat, watermelons hate the cold, so don’t start your crop until all danger of frost has passed. In North Texas the last chance of frost is usually (but not always) around March 17. You can begin sowing them on or after that date. Another way to judge when to plant is to wait until the soil temperature warms to at least 70°F. This will help avoid poor germination.

Because we have a long growing season, you can continue planting through late July and still harvest fruits before the first winter frost. See our Vegetable Planting Calendar developed especially for North Texas.

Where To Plant

Watermelons need lots of sun, lots of nutrients, and lots of room, so follow these three planting guidelines:

  • Place them in FULL SUN — they thrive in the heat

  • Plant in rich, well composted loamy soil

  • Plant spacing varies depending on the variety and size of the mature melon.

Preparing Your Planting Area

Plant where there is plenty of open ground. Vines can reach 20 feet in length. Give them plenty of space to sprawl out, or provide a sturdy trellis, such as a chain link fence, for vertical support.

The conventional way to grow them is to plant them in raised rows, known as hills. Hilling ensures good drainage and will hold the sun’s heat longer. Other options include growing them in a raised bed or large container, or even planting directly in a bag of Black Kow composted cow manure.

Nutrient-hungry watermelons need extremely rich soil and regular fertilization to grow and produce fruit. If you plant them in the ground, you must heavily amend your soil with lots of organic matter such as compost or composted cow manure. Include a balanced fertilizer that is high in nitrogen. Planting directly in a raised bed of compost or Soil Mender Raised Bed Mix makes it easier to ensure they’re getting all the nutrients they need and allows the vines spread in every direction.

Tip: Consider growing your melons in the middle of the lawn. Just dump two or three bags of Black Kow composted cow manure into a heap on the lawn. Plant six to eight seeds in your pile and water well. You can thin them out later if need be. You’ll have to mow around the vines but their foliage will shade the grass underneath it and slow growth. After harvest, pull out the vines and rake the soil over the lawn. The remaining compost will act as a lawn fertilizer and within a week or so, the grass will be growing vigorously again.

How to Plant

Since our growing season is watermelon friendly, we recommend sowing seeds directly outdoors, rather than starting them indoors and then transplanting them. This will save you time and reduce the risk associated with transplanting young plants. You can also buy high quality watermelon starts from us.

It’s extremely important with seeds and young plants that you stimulate root development. We recommend that you pre-soak seeds overnight in a solution of Maxicrop Liquid Seaweed. Liquid seaweed is a natural root stimulator.

Plants can also experience “transplant shock.” To avoid this, always transfer plants from wet soil to wet soil using Marshall Grain's planting recipe.

Begin by sowing eight to 10 watermelon seeds in a hill, and push seeds 1 inch into the soil. Space hills 3 to 4 feet apart, with at least 8 feet between rows. Thin plants to the 3 best in each hill. Keep soil free of weeds by shallow hoeing or with a layer of mulch.

Care and Maintenance

Tip: Melons need to be kept off the ground to prevent rotting. One way to do this is to make a sling or hammock to hold the growing watermelons in the air without pulling the vines from the fence. This method works best with smaller watermelons, because larger melons would tax almost any makeshift sling system.


Watering is very important. While melon plants are growing, blooming, and setting fruit, they need 1 to 2 inches of water per week. Keep soil moist, but not waterlogged. Hand water at the vine’s base in the morning, and try to avoid wetting the leaves.

Reduce watering once fruit are growing. Once fruits are about the size of a tennis ball, reduce your watering. Only water if the soil is dry and leaves show signs of wilting. Dry weather produces the sweetest melon.


As the vines are developing, use a high-nitrogen organic fertilizer such as 5-1-1 or 12-0-0. After flowering begins, switch to a fertilizer with less nitrogen. Side dress your plants with a high quality organic fertilizer such as Espoma 5-1-1. Fertilize again when the melons are set.

Tip: When vines begin to ramble, give watermelon plants a dose of boron to help them produce sweeter fruits. Dissolve 1 tablespoon of household borax in 1 gallon of water and spray foliage and the base of the plants.

If fruits are allowed to sit on bare soil, they will tend to rot and/or encourage sow bugs and other insects to damage the melon. Prevent these issues by gently lifting each melon and putting cardboard, straw, or mulch between the fruit and the soil. You can also use pots or pieces of wood.

If you want to trellis your plants, you can take some of the strain off the vines by supporting the fruit with slings made from netting, fabric, or pantyhose. Trellising also improves air circulation around plants and can help reduce foliar disease problems. Choose small-fruited varieties and reduce plant spacing.

Pests & Diseases

Watermelons are most likely to be attacked by cucumber beetles or squash vine borers. They can also attract aphids. Floating row covers are not recommended because they may interefere with pollination. A better option would be to put out squash vine borer traps, or release Trichogramma Wasps. Vine borer traps lure the adult vine borer moth away from your plants, while trichogramma wasps parasitize the eggs of the vine borer.

Cucumber beetles can be controlled by spraying plants with Triple Action or by dusting with diatomaceous earth (DE).

Fusarium Wilt

Fusarium wilt is a widespread plant disease caused by the fungus that inhabits the soil. It thrives in warm temperatures (75 degrees F) and can stay in the soil for many years, even when no host plants are present.

Fusarium Wilt on tabacco - wikipedia
Fusarium Wilt attacks many different kinds of plants, including watermelons.

Plants may start out with healthy dark green leaves, but as the infection progresses the leaves become pale, wilt, wither, and die. As they die, the lower leaves of the diseased plants begin to drop off and the symptoms move progressively to the upper leaves.

To reduce the chance of diseases and insect infestations practice crop rotation and avoid planting cucumber family crops (melons, squash, pumpkins) in the same spot two years in a row.


Watermelons don’t get any sweeter after they are picked, so harvest time is crucial. They generally ripen over two weeks so keep your eye on them. The surest sign of ripeness in most watermelon varieties is the color of the bottom spot where the melon sits on the ground. As the watermelon matures, the spot turns from white to yellow. Also, unripe fruit will have a slick skin while ripened fruit will feel slightly sticky.


Recent Posts

See All


Commenting has been turned off.
bottom of page